Buccal Cavity of a Frog

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Gross Anatomy of a Frog
aldreyarellano

I. AXIAL REGION
A. Head – most anterior, triangular part w/c is flattened dorso-ventrally 1. Snout – blunt apex of the head
2. Mouth – large anterior opening w/c extends postero-laterally up to the head’s base > dorsal & ventral lip folds – immovable folds that border the mouth dorsally & ventrally – provided w/ valves w/c are associated to respiratory movements – provided w/ valves w/c are associated to respiratory movements 3. External nares or nostril – pair of slit-like openings immediately postero-lateral to snout

4. Eyes – pair of large structures w/c protrude on the dorso-lateral sides of the head and posterior to the nostrils. > Upper Eyelid – thicker structure; borders the eye dorsally; very little movement > Lower Eyelid – thinner structure; borders the eye ventrally; more movable > Third Eyelid or nictitating membrane – thin, transparent, freely movable membrane w/c continuous w/ the inner fold of the lower eyelid.

– homologous to the vestigial PLICA SEMILUNARIS – a fold like structure located near the median corner of the human eye. > Orbit or eye socket – socket where eyes retract
> Cornea – exposed transparent part of the eye
> Conjunctiva – thin transparent membrane w/c is continuous w/ the inner surface of the eyelids. > Conjunctiva – lies and inseparably adheres to the outer surface of the cornea > Pupil – dark, centrally located opening through w/c light can enter the eye > Iris – pigmented, curtain-like structure w/c surrounds the pupil > Iris – regulates the size of the pupil depending upon the intensity of light > Browspot – small, lighter-colored circular spot at about the anterior level of the eye > Tympanic membrane (Tympanum) – smooth, somewhat circular, thin membrane, postero-lateral to the eye. B. Trunk – much bigger part of the body & is situated posterior to the head, having no distinct neck 1. Hump – distinct dorsal elevation about the middle of the trunk; due to the articulation of the ilia of the pelvic girdle w/ the transverse processes of the sacral vertebra. 2. Anus – common terminal opening of the digestive and urogenital system at the posterior part of the trunk.

II. APPENDICULAR REGION
A. Forelimbs – smaller shorter pair of appendages that arise from the anterior part of the trunk. Function: raise or support the body of the frog when at rest Division:
> Upper arm – proximal division of the forelimb
> Lower arm / forearm – middle division
> Manus or hands – distal division of the forelimb
a. carpus / wrist – proximal division of the humanus
b. palm – middle division
c. digits / fingers – distal division
d. axilla / axillae or axillary fossa / armpit – angular depression found between the upper arm & the trunk B. Hindlimbs – bigger & lower pair of appendages arising from the posterior part of the trunk. Function: adapted for jumping & swimming Division:

a. thigh – proximal division of the hindlimb
b. shank – middle division
c. pes / foot – distal division
web – a membranous extension of the skin; aids for swimming d. prehallux / calcar – rudiment of the 6th toe

External Characteristic of Male/Female Frog

Male

> w/ distinct dark pigments of the skin due to concentration of pigments > enlarged or swollen thumb pads of the inner finger during breeding season Function: for grasping the female frogs during amplexus or dales copulation > sexually mature male frogs are generally smaller than sexually mature female > presence of a slit-like structure (opening of the vocal sac) on the floor of the mouth – acts as resonators of sound

Male

> w/ distinct dark pigments of the skin due to concentration of pigments > enlarged or swollen thumb pads of the inner finger during breeding season Function: for grasping the female frogs during amplexus or dales copulation > sexually mature male frogs are generally smaller than sexually mature female > presence of a slit-like structure (opening of the vocal...
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